C# Compiler Error Codes CS8001 to CS8500

In this post, you’ll learn all the C# compiler error and warnings from the code CS8001 to CS8500.

C# Compiler Error Codes CS8001 to CS8500

Error CodeTypeError/Warning Description
CS8001WarningThe command line switch ‘{0}’ is not yet implemented and was ignored.
CS8002WarningReferenced assembly ‘{0}’ does not have a strong name.
CS8003ErrorInvalid signature public key specified in AssemblySignatureKeyAttribute.
CS8004ErrorType ‘{0}’ exported from module ‘{1}’ conflicts with type declared in primary module of this assembly.
CS8005ErrorType ‘{0}’ exported from module ‘{1}’ conflicts with type ‘{2}’ exported from module ‘{3}’.
CS8006ErrorForwarded type ‘{0}’ conflicts with type declared in primary module of this assembly.
CS8007ErrorType ‘{0}’ forwarded to assembly ‘{1}’ conflicts with type ‘{2}’ forwarded to assembly ‘{3}’.
CS8008ErrorType ‘{0}’ forwarded to assembly ‘{1}’ conflicts with type ‘{2}’ exported from module ‘{3}’.
CS8009WarningReferenced assembly ‘{0}’ has different culture setting of ‘{1}’.
CS8010ErrorAgnostic assembly cannot have a processor specific module ‘{0}’.
CS8011ErrorAssembly and module ‘{0}’ cannot target different processors.
CS8012WarningReferenced assembly ‘{0}’ targets a different processor.
CS8013ErrorCryptographic failure while creating hashes.
CS8014ErrorReference to ‘{0}’ netmodule missing.
CS8015ErrorModule ‘{0}’ is already defined in this assembly. Each module must have a unique filename.
CS8016ErrorTransparent identifier member access failed for field ‘{0}’ of ‘{1}’. Does the data being queried implement the query pattern?
CS8017ErrorThe parameter has multiple distinct default values.
CS8018WarningWithin cref attributes, nested types of generic types should be qualified.
CS8019HiddenUnnecessary using directive.
CS8020HiddenUnused extern alias.
CS8021WarningNo value for RuntimeMetadataVersion found. No assembly containing System.Object was found nor was a value for RuntimeMetadataVersion specified through options.
CS8022ErrorFeature ‘{0}’ is not available in C# 1. Please use language version {1} or greater.
CS8023ErrorFeature ‘{0}’ is not available in C# 2. Please use language version {1} or greater.
CS8024ErrorFeature ‘{0}’ is not available in C# 3. Please use language version {1} or greater.
CS8025ErrorFeature ‘{0}’ is not available in C# 4. Please use language version {1} or greater.
CS8026ErrorFeature ‘{0}’ is not available in C# 5. Please use language version {1} or greater.
CS8027ErrorThe field has multiple distinct constant values.
CS8028Error‘{0}’: a class with the ComImport attribute cannot specify field initializers.
CS8029WarningLocal name ‘{0}’ is too long for PDB. Consider shortening or compiling without /debug.
CS8030ErrorAnonymous function converted to a void returning delegate cannot return a value
CS8031ErrorAsync lambda expression converted to a ‘Task’ returning delegate cannot return a value. Did you intend to return ‘Task\<T\>‘?
CS8032WarningAn instance of analyzer {0} cannot be created from {1} : {2}.
CS8033WarningThe assembly {0} does not contain any analyzers.
CS8034WarningUnable to load Analyzer assembly {0} : {1}
CS8035ErrorError reading ruleset file {0} – {1}
CS8036ErrorError reading debug information for ‘{0}’
CS8040InfoSkipping some types in analyzer assembly {0} due to a ReflectionTypeLoadException : {1}.
CS8050ErrorOnly auto-implemented properties can have initializers.
CS8051ErrorAuto-implemented properties must have get accessors.
CS8053ErrorInstance properties in interfaces cannot have initializers.
CS8054ErrorEnums cannot contain explicit parameterless constructors
CS8055ErrorCannot emit debug information for a source text without encoding.
CS8057ErrorBlock bodies and expression bodies cannot both be provided.
CS8058ErrorFeature ‘{0}’ is experimental and unsupported; use ‘/features:{1}’ to enable.
CS8059ErrorFeature ‘{0}’ is not available in C# 6. Please use language version {1} or greater.
CS8070ErrorControl cannot fall out of switch from final case label (‘{0}’)
CS8072ErrorAn expression tree lambda may not contain a null propagating operator.
CS8073WarningThe result of the expression is always ‘{0}’ since a value of type ‘{1}’ is never equal to ‘null’ of type ‘{2}’
CS8074ErrorAn expression tree lambda may not contain a dictionary initializer.
CS8075ErrorAn extension Add method is not supported for a collection initializer in an expression lambda.
CS8076ErrorMissing close delimiter ‘}’ for interpolated expression started with ‘{‘.
CS8078ErrorAn expression is too long or complex to compile
CS8079ErrorUse of possibly unassigned auto-implemented property ‘{0}’
CS8080ErrorAuto-implemented properties must override all accessors of the overridden property.
CS8081ErrorExpression does not have a name.
CS8082ErrorSub-expression cannot be used in an argument to nameof.
CS8083ErrorAn alias-qualified name is not an expression.
CS8084ErrorType parameters are not allowed on a method group as an argument to ‘nameof’.
CS8085ErrorA ‘using static’ directive cannot be used to declare an alias
CS8086ErrorA ‘{0}’ character must be escaped (by doubling) in an interpolated string.
CS8087ErrorA ‘{0}’ character may only be escaped by doubling ‘{0}{0}’ in an interpolated string.
CS8088ErrorA format specifier may not contain trailing whitespace.
CS8089ErrorEmpty format specifier.
CS8090ErrorThere is an error in a referenced assembly ‘{0}’.
CS8091Error‘{0}’ cannot be extern and have a constructor initializer
CS8092ErrorExpression or declaration statement expected.
CS8093ErrorExtension method groups are not allowed as an argument to ‘nameof’.
CS8094WarningAlignment value {0} has a magnitude greater than {1} and may result in a large formatted string.
CS8095ErrorLength of String constant resulting from concatenation exceeds System.Int32.MaxValue. Try splitting the string into multiple constants.
CS8096ErrorDebug entry point must be a definition of a method declared in the current compilation.
CS8097Error#load is only allowed in scripts
CS8098ErrorCannot use #load after first token in file
CS8099ErrorSource file references are not supported.
CS8100ErrorThe ‘await’ operator cannot be used in a static script variable initializer.
CS8101ErrorThe pathmap option was incorrectly formatted.
CS8102ErrorPublic signing was specified and requires a public key, but no public key was specified.
CS8103ErrorCombined length of user strings used by the program exceeds allowed limit. Try to decrease use of string literals.
CS8104ErrorAn error occurred while writing the output file: {0}.
CS8105WarningAttribute ‘{0}’ is ignored when public signing is specified.
CS8106ErrorOption ‘{0}’ must be an absolute path.
CS8107ErrorFeature ‘{0}’ is not available in C# 7.0. Please use language version {1} or greater.
CS8108ErrorCannot pass argument with dynamic type to params parameter ‘{0}’ of local function ‘{1}’.
CS8110ErrorAn expression tree may not contain a reference to a local function
CS8111ErrorInvalid instrumentation kind: {0}
CS8112ErrorLocal function ‘{0}’ must declare a body because it is not marked ‘static extern’.
CS8113ErrorInvalid hash algorithm name: ‘{0}’
CS8115ErrorA throw expression is not allowed in this context.
CS8116ErrorIt is not legal to use nullable type ‘{0}?’ in a pattern; use the underlying type ‘{0}’ instead.
CS8117ErrorInvalid operand for pattern match; value required, but found ‘{0}’.
CS8119ErrorThe switch expression must be a value; found ‘{0}’.
CS8120ErrorThe switch case is unreachable. It has already been handled by a previous case or it is impossible to match.
CS8121ErrorAn expression of type ‘{0}’ cannot be handled by a pattern of type ‘{1}’.
CS8122ErrorAn expression tree may not contain an ‘is’ pattern-matching operator.
CS8123WarningThe tuple element name ‘{0}’ is ignored because a different name or no name is specified by the target type ‘{1}’.
CS8124ErrorTuple must contain at least two elements.
CS8125ErrorTuple element name ‘{0}’ is only allowed at position {1}.
CS8126ErrorTuple element name ‘{0}’ is disallowed at any position.
CS8127ErrorTuple element names must be unique.
CS8128ErrorMember ‘{0}’ was not found on type ‘{1}’ from assembly ‘{2}’.
CS8129ErrorNo suitable ‘Deconstruct’ instance or extension method was found for type ‘{0}’, with {1} out parameters and a void return type.
CS8130ErrorCannot infer the type of implicitly-typed deconstruction variable ‘{0}’.
CS8131ErrorDeconstruct assignment requires an expression with a type on the right-hand-side.
CS8132ErrorCannot deconstruct a tuple of ‘{0}’ elements into ‘{1}’ variables.
CS8133ErrorCannot deconstruct dynamic objects.
CS8134ErrorDeconstruction must contain at least two variables.
CS8135ErrorTuple with {0} elements cannot be converted to type ‘{1}’.
CS8136ErrorDeconstruction ‘var (…)’ form disallows a specific type for ‘var’.
CS8137ErrorCannot define a class or member that utilizes tuples because the compiler required type ‘{0}’ cannot be found. Are you missing a reference?
CS8138ErrorCannot reference ‘System.Runtime.CompilerServices.TupleElementNamesAttribute’ explicitly. Use the tuple syntax to define tuple names.
CS8139Error‘{0}’: cannot change tuple element names when overriding inherited member ‘{1}’
CS8140Error‘{0}’ is already listed in the interface list on type ‘{2}’ with different tuple element names, as ‘{1}’.
CS8141ErrorThe tuple element names in the signature of method ‘{0}’ must match the tuple element names of interface method ‘{1}’ (including on the return type).
CS8142ErrorBoth partial method declarations, ‘{0}’ and ‘{1}’, must use the same tuple element names.
CS8143ErrorAn expression tree may not contain a tuple literal.
CS8144ErrorAn expression tree may not contain a tuple conversion.
CS8145ErrorAuto-implemented properties cannot return by reference
CS8146ErrorProperties which return by reference must have a get accessor
CS8147ErrorProperties which return by reference cannot have set accessors
CS8148Error‘{0}’ must match by reference return of overridden member ‘{1}’
CS8149ErrorBy-reference returns may only be used in methods that return by reference
CS8150ErrorBy-value returns may only be used in methods that return by value
CS8151ErrorThe return expression must be of type ‘{0}’ because this method returns by reference
CS8152Error‘{0}’ does not implement interface member ‘{1}’. ‘{2}’ cannot implement ‘{1}’ because it does not have matching return by reference.
CS8153ErrorAn expression tree lambda may not contain a call to a method, property, or indexer that returns by reference
CS8154ErrorThe body of ‘{0}’ cannot be an iterator block because ‘{0}’ returns by reference
CS8155ErrorLambda expressions that return by reference cannot be converted to expression trees
CS8156ErrorAn expression cannot be used in this context because it may not be passed or returned by reference
CS8157ErrorCannot return ‘{0}’ by reference because it was initialized to a value that cannot be returned by reference
CS8158ErrorCannot return by reference a member of ‘{0}’ because it was initialized to a value that cannot be returned by reference
CS8159ErrorCannot return the range variable ‘{0}’ by reference
CS8160ErrorA readonly field cannot be returned by writable reference
CS8161ErrorA static readonly field cannot be returned by writable reference
CS8162ErrorMembers of readonly field ‘{0}’ cannot be returned by writable reference
CS8163ErrorFields of static readonly field ‘{0}’ cannot be returned by writable reference
CS8166ErrorCannot return a parameter by reference ‘{0}’ because it is not a ref parameter
CS8167ErrorCannot return by reference a member of parameter ‘{0}’ because it is not a ref or out parameter
CS8168ErrorCannot return local ‘{0}’ by reference because it is not a ref local
CS8169ErrorCannot return a member of local ‘{0}’ by reference because it is not a ref local
CS8170ErrorStruct members cannot return ‘this’ or other instance members by reference
CS8171ErrorCannot initialize a by-value variable with a reference
CS8172ErrorCannot initialize a by-reference variable with a value
CS8173ErrorThe expression must be of type ‘{0}’ because it is being assigned by reference
CS8174ErrorA declaration of a by-reference variable must have an initializer
CS8175ErrorCannot use ref local ‘{0}’ inside an anonymous method, lambda expression, or query expression
CS8176ErrorIterators cannot have by-reference locals
CS8177ErrorAsync methods cannot have by-reference locals
CS8178Error‘await’ cannot be used in an expression containing a call to ‘{0}’ because it returns by reference
CS8179ErrorPredefined type ‘{0}’ is not defined or imported
CS8180Error{ or ; or => expected
CS8181Error‘new’ cannot be used with tuple type. Use a tuple literal expression instead.
CS8182ErrorPredefined type ‘{0}’ must be a struct.
CS8183ErrorCannot infer the type of implicitly-typed discard.
CS8185ErrorA declaration is not allowed in this context.
CS8186ErrorA foreach loop must declare its iteration variables.
CS8187ErrorTuple element names are not permitted on the left of a deconstruction.
CS8188ErrorAn expression tree may not contain a throw-expression.
CS8189ErrorRef mismatch between ‘{0}’ and delegate ‘{1}’
CS8190ErrorProvided source code kind is unsupported or invalid: ‘{0}’
CS8191ErrorProvided documentation mode is unsupported or invalid: ‘{0}’.
CS8192ErrorProvided language version is unsupported or invalid: ‘{0}’.
CS8196ErrorReference to an implicitly-typed out variable ‘{0}’ is not permitted in the same argument list.
CS8197ErrorCannot infer the type of implicitly-typed out variable ‘{0}’.
CS8198ErrorAn expression tree may not contain an out argument variable declaration.
CS8199ErrorThe syntax ‘var (…)’ as an lvalue is reserved.
CS8202ErrorPublic signing is not supported for netmodules.
CS8203ErrorInvalid assembly name: {0}
CS8204ErrorFor type ‘{0}’ to be used as an AsyncMethodBuilder for type ‘{1}’, its Task property should return type ‘{1}’ instead of type ‘{2}’.
CS8206ErrorModule ‘{0}’ in assembly ‘{1}’ is forwarding the type ‘{2}’ to multiple assemblies: ‘{3}’ and ‘{4}’.
CS8207ErrorAn expression tree may not contain a discard.
CS8208ErrorIt is not legal to use the type ‘dynamic’ in a pattern.
CS8209ErrorA value of type ‘void’ may not be assigned.
CS8210ErrorA tuple may not contain a value of type ‘void’.
CS8300ErrorMerge conflict marker encountered
CS8301ErrorInvalid name for a preprocessing symbol; ‘{0}’ is not a valid identifier
CS8302ErrorFeature ‘{0}’ is not available in C# 7.1. Please use language version {1} or greater.
CS8303ErrorSpecified language version ‘{0}’ cannot have leading zeroes
CS8304ErrorCompiler version: ‘{0}’. Language version: {1}.
CS8305Warning‘{0}’ is for evaluation purposes only and is subject to change or removal in future updates.
CS8306ErrorTuple element name ‘{0}’ is inferred. Please use language version {1} or greater to access an element by its inferred name.
CS8307ErrorThe first operand of an ‘as’ operator may not be a tuple literal without a natural type.
CS8308ErrorDo not use refout when using refonly.
CS8309ErrorCannot compile net modules when using /refout or /refonly.
CS8310ErrorOperator ‘{0}’ cannot be applied to operand ‘{1}’
CS8312ErrorUse of default literal is not valid in this context
CS8314ErrorAn expression of type ‘{0}’ cannot be handled by a pattern of type ‘{1}’ in C# {2}. Please use language version {3} or greater.
CS8315ErrorOperator ‘{0}’ is ambiguous on operands ‘{1}’ and ‘{2}’
CS8320ErrorFeature ‘{0}’ is not available in C# 7.2. Please use language version {1} or greater.
CS8321WarningThe local function ‘{0}’ is declared but never used
CS8322ErrorCannot pass argument with dynamic type to generic local function ‘{0}’ with inferred type arguments.
CS8323ErrorNamed argument ‘{0}’ is used out-of-position but is followed by an unnamed argument
CS8324ErrorNamed argument specifications must appear after all fixed arguments have been specified in a dynamic invocation.
CS8325Error‘await’ cannot be used in an expression containing a ref conditional operator
CS8326ErrorBoth conditional operator values must be ref values or neither may be a ref value
CS8327ErrorThe expression must be of type ‘{0}’ to match the alternative ref value
CS8328ErrorThe parameter modifier ‘{0}’ cannot be used with ‘{1}’
CS8329ErrorCannot use {0} ‘{1}’ as a ref or out value because it is a readonly variable
CS8330ErrorMembers of {0} ‘{1}’ cannot be used as a ref or out value because it is a readonly variable
CS8331ErrorCannot assign to {0} ‘{1}’ because it is a readonly variable
CS8332ErrorCannot assign to a member of {0} ‘{1}’ because it is a readonly variable
CS8333ErrorCannot return {0} ‘{1}’ by writable reference because it is a readonly variable
CS8334ErrorMembers of {0} ‘{1}’ cannot be returned by writable reference because it is a readonly variable
CS8335ErrorDo not use ‘{0}’. This is reserved for compiler usage.
CS8336ErrorThe type name ‘{0}’ is reserved to be used by the compiler.
CS8337ErrorThe first parameter of a ‘ref’ extension method ‘{0}’ must be a value type or a generic type constrained to struct.
CS8338ErrorThe first parameter of the ‘in’ extension method ‘{0}’ must be a concrete (non-generic) value type.
CS8340ErrorInstance fields of readonly structs must be readonly.
CS8341ErrorAuto-implemented instance properties in readonly structs must be readonly.
CS8342ErrorField-like events are not allowed in readonly structs.
CS8343Error‘{0}’: ref structs cannot implement interfaces
CS8344Errorforeach statement cannot operate on enumerators of type ‘{0}’ in async or iterator methods because ‘{0}’ is a ref struct.
CS8345ErrorField or auto-implemented property cannot be of type ‘{0}’ unless it is an instance member of a ref struct.
CS8346ErrorConversion of a stackalloc expression of type ‘{0}’ to type ‘{1}’ is not possible.
CS8347ErrorCannot use a result of ‘{0}’ in this context because it may expose variables referenced by parameter ‘{1}’ outside of their declaration scope
CS8348ErrorCannot use a member of result of ‘{0}’ in this context because it may expose variables referenced by parameter ‘{1}’ outside of their declaration scope
CS8349ErrorExpression cannot be used in this context because it may indirectly expose variables outside of their declaration scope
CS8350ErrorThis combination of arguments to ‘{0}’ is disallowed because it may expose variables referenced by parameter ‘{1}’ outside of their declaration scope
CS8351ErrorBranches of a ref conditional operator cannot refer to variables with incompatible declaration scopes
CS8352ErrorCannot use variable ‘{0}’ in this context because it may expose referenced variables outside of their declaration scope
CS8353ErrorA result of a stackalloc expression of type ‘{0}’ cannot be used in this context because it may be exposed outside of the containing method
CS8354ErrorCannot return ‘this’ by reference.
CS8355ErrorAn in parameter cannot have the Out attribute.
CS8356ErrorPredefined type ‘{0}’ is declared in multiple referenced assemblies: ‘{1}’ and ‘{2}’
CS8357ErrorThe specified version string contains wildcards, which are not compatible with determinism. Either remove wildcards from the version string, or disable determinism for this compilation
CS8358ErrorCannot use attribute constructor ‘{0}’ because it has ‘in’ parameters.
CS8359WarningFilter expression is a constant ‘false’, consider removing the catch clause
CS8360WarningFilter expression is a constant ‘false’, consider removing the try-catch block
CS8361ErrorA conditional expression cannot be used directly in a string interpolation because the ‘:’ ends the interpolation. Parenthesize the conditional expression.
CS8362Error__arglist cannot have an argument of void type
CS8364ErrorArguments with ‘in’ modifier cannot be used in dynamically dispatched expressions.
CS8370ErrorFeature ‘{0}’ is not available in C# 7.3. Please use language version {1} or greater.
CS8371WarningField-targeted attributes on auto-properties are not supported in language version {0}. Please use language version {1} or greater.
CS8372ErrorDo not use ‘System.Runtime.CompilerServices.FixedBuffer’ attribute on a property
CS8373ErrorThe left-hand side of a ref assignment must be a ref variable.
CS8374ErrorCannot ref-assign ‘{1}’ to ‘{0}’ because ‘{1}’ has a narrower escape scope than ‘{0}’.
CS8375ErrorThe ‘new()’ constraint cannot be used with the ‘unmanaged’ constraint
CS8377ErrorThe type ‘{2}’ must be a non-nullable value type, along with all fields at any level of nesting, in order to use it as parameter ‘{1}’ in the generic type or method ‘{0}’
CS8378Error__arglist cannot have an argument passed by ‘in’ or ‘out’
CS8379ErrorType parameter ‘{1}’ has the ‘unmanaged’ constraint so ‘{1}’ cannot be used as a constraint for ‘{0}’
CS8380Error‘{0}’: cannot specify both a constraint class and the ‘unmanaged’ constraint
CS8381Error“Invalid rank specifier: expected ‘]’
CS8382ErrorAn expression tree may not contain a tuple == or != operator
CS8383WarningThe tuple element name ‘{0}’ is ignored because a different name or no name is specified on the other side of the tuple == or != operator.
CS8384ErrorTuple types used as operands of an == or != operator must have matching cardinalities. But this operator has tuple types of cardinality {0} on the left and {1} on the right.
CS8385ErrorThe given expression cannot be used in a fixed statement
CS8386ErrorInvalid object creation
CS8387WarningType parameter ‘{0}’ has the same name as the type parameter from outer method ‘{1}’
CS8388ErrorAn out variable cannot be declared as a ref local
CS8389ErrorOmitting the type argument is not allowed in the current context
CS8400ErrorFeature ‘{0}’ is not available in C# 8.0. Please use language version {1} or greater.
CS8401ErrorTo use ‘@$’ instead of ‘[email protected]’ for an interpolated verbatim string, please use language version ‘{0}’ or greater.
CS8403ErrorMethod ‘{0}’ with an iterator block must be ‘async’ to return ‘{1}’
CS8410Error‘{0}’: type used in an asynchronous using statement must be implicitly convertible to ‘System.IAsyncDisposable’ or implement a suitable ‘DisposeAsync’ method.
CS8411ErrorAsynchronous foreach statement cannot operate on variables of type ‘{0}’ because ‘{0}’ does not contain a suitable public instance or extension definition for ‘{1}’
CS8412ErrorAsynchronous foreach requires that the return type ‘{0}’ of ‘{1}’ must have a suitable public ‘MoveNextAsync’ method and public ‘Current’ property
CS8413ErrorAsynchronous foreach statement cannot operate on variables of type ‘{0}’ because it implements multiple instantiations of ‘{1}’; try casting to a specific interface instantiation
CS8414Errorforeach statement cannot operate on variables of type ‘{0}’ because ‘{0}’ does not contain a public instance or extension definition for ‘{1}’. Did you mean ‘await foreach’ rather than ‘foreach’?
CS8415ErrorAsynchronous foreach statement cannot operate on variables of type ‘{0}’ because ‘{0}’ does not contain a public instance or extension definition for ‘{1}’. Did you mean ‘foreach’ rather than ‘await foreach’?
CS8416ErrorCannot use a collection of dynamic type in an asynchronous foreach
CS8417Error‘{0}’: type used in an asynchronous using statement must be implicitly convertible to ‘System.IAsyncDisposable’ or implement a suitable ‘DisposeAsync’ method. Did you mean ‘using’ rather than ‘await using’?
CS8418Error‘{0}’: type used in a using statement must be implicitly convertible to ‘System.IDisposable’. Did you mean ‘await using’ rather than ‘using’?
CS8419ErrorThe body of an async-iterator method must contain a ‘yield’ statement.
CS8420ErrorThe body of an async-iterator method must contain a ‘yield’ statement. Consider removing ‘async’ from the method declaration or adding a ‘yield’ statement.
CS8421ErrorA static local function cannot contain a reference to ‘{0}’.
CS8422ErrorA static local function cannot contain a reference to ‘this’ or ‘base’.
CS8423ErrorAttribute ‘{0}’ is not valid on event accessors. It is only valid on ‘{1}’ declarations.
CS8424WarningThe EnumeratorCancellationAttribute applied to parameter ‘{0}’ will have no effect. The attribute is only effective on a parameter of type CancellationToken in an async-iterator method returning IAsyncEnumerable
CS8425WarningAsync-iterator ‘{0}’ has one or more parameters of type ‘CancellationToken’ but none of them is decorated with the ‘EnumeratorCancellation’ attribute, so the cancellation token parameter from the generated ‘IAsyncEnumerable\<>.GetAsyncEnumerator’ will be unconsumed
CS8426ErrorThe attribute [EnumeratorCancellation] cannot be used on multiple parameters
CS8427ErrorEnums, classes, and structures cannot be declared in an interface that has an ‘in’ or ‘out’ type parameter.
CS8428ErrorInvocation of implicit Index Indexer cannot name the argument.
CS8429ErrorInvocation of implicit Range Indexer cannot name the argument.
CS8500WarningThis takes the address of, gets the size of, or declares a pointer to a managed type (‘{0}’)